A
A.When the marginal benefit of removing an extra ton of carbon dioxide is less than the marginal cost of removing the extra ton
B
B.When the marginal benefit of removing an extra ton of carbon dioxide equals the marginal cost of removing the extra ton
C
C.When the marginal cost of removing an extra ton of carbon dioxide is less than 0
D
D.When the marginal benefit of removing an extra ton of carbon dioxide is 0
